Robotic Technology Inc.'s Energetically Autonomous Tactical Robot -- that's right, "EATR" -- "can find, ingest, and extract energy from biomass in the environment (and other organically-based energy sources), as well as use conventional and alternative fuels (such as gasoline, heavy fuel, kerosene, diesel, propane, coal, cooking oil, and solar) when suitable," reads the company's Web site.
That "biomass" and "other organically-based energy sources" wouldn't necessarily be limited to plant material -- animal and human corpses contain plenty of energy, and they'd be plentiful in a war zone.
AAAAAAAAAAAAAAAAAHH! I'm okay, I'm okay. AAAAAAAAAAAAAAAAH! No I'm not. Hold me. Lower. Little lower. Lower. What?! THIS COULD BE OUR LAST NIGHT ALIVE!
Thanks to everyone who sent this in. No, really, thanks -- I hate sleeping. WITH YOUR SISTER! (snores)